“Tern Island” Now Supporting Nesting of Three Protected Shorebird Species


Nestled along the eastern shoreline of the San Francisco Bay is a bird sanctuary built by thousands of volunteers. After twelve years of success, “Tern Island,” as it is commonly known, provides nesting habitat for three special-status birds. “Tern Island” was built between 2001 and 2004 by volunteers who moved tons of sand and oyster shells together to create an artificial island, perfect for shorebird nesting.

“Tern Island” supports the second largest colony of endangered California least terns north of Ventura County and has the highest breeding densities of all California least terns on the West Coast. The smallest of North American terns, the California tern was once abundant along the Pacific Coast, but it is listed as a federal and California state endangered species.

“Tern Island” also now supports the nesting of the threatened western snowy plovers and the black skimmer, a species of special concern, bringing the total special-status birds successfully nesting at “Tern Island” to three. Habitat loss, non-native predators, and environmental contaminants have taken a toll on shorebirds. “Tern Island” provides these and other shorebirds with additional nesting habitat.

Volunteers are vital in monitoring the colonies each year, and removing invasive plants. In addition to the support of volunteers, who have contributed over 25,000 hours of labor in the past decade, the project benefits from financial sponsorship from the Regional Parks Foundation, US Fish & Wildlife, and dozens of stakeholder organizations and sponsors over the years.

The nests are in a protected area, restricted from the public; park visitors may view an interpretive panel and glimpse views of the birds from the south end of Cogswell Marsh. To get involved, call or email EBRPD Wildlife Biologist Dave “Doc Quack” Riensche at (510) 544-2319 ( or visit

The East Bay Regional Park District is the largest regional park system in the nation, comprising 73 parks, 55 miles of shoreline, and 1,250 miles of trails for hiking, biking, horseback riding, and nature learning. The Park District receives more than 25 million visits annually throughout Alameda and Contra Costa counties in the San Francisco Bay Area.

Dave Mason, Public Information Supervisor
(510) 544-2217